Promising long-term outcomes after bariatric surgery in adolescence

medwireNews: Two studies of patients who underwent bariatric surgery during adolescence reveal sustained weight loss and improved cardiovascular risk factors 5 years or more after the procedure.

However, this came at the cost of nutritional deficiencies in the majority of patients, show the findings in The Lancet Diabetes & Endocrinology. Many patients also required additional surgical interventions, and anemia was common.

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Lifelong follow-up, although challenging in young people, is essential, as these individuals still have a significant amount of co-morbidity, some of which may be related to the surgical procedure.

The first study, from Torsten Olbers (University of Gothenburg, Sweden) and colleagues, reports the 5-year outcomes of 81 patients who had undergone Roux-en-Y gastric bypass at an average age of 16.5 years, at which time they had an average body mass index (BMI) of 45.5 kg/m2.

Patients’ average BMI reduction over the following 5 years was 13.1 kg/m2, with 37% no longer obese after 5 years. Weight loss varied, however, with 31% not losing at least 20% of their bodyweight. Most weight loss occurred during the first year, with average weight rising again over the next 4 years, albeit only slightly.

The extent and pattern of weight change was similar to that in 81 patients who had undergone Roux-en-Y gastric bypass as adults, but 80 patients who had been managed conservatively as adolescents had an average BMI increase of 3.3 kg/m2. A quarter of these patients underwent bariatric surgery during follow-up, when they reached adulthood.

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There were similar findings in the second study, which involved 58 US patients who had undergone surgery at an average age of 17.1 years, when their average BMI was 58.5 kg/m2. Thomas Inge (Cincinnati Children's Hospital Medical Center, Ohio, USA) and team report that the patients’ BMI fell by an average 22.8 kg/m2 during the first year, and although it rose slightly during an average 8 years of total follow-up, the reduction remained substantial, at an average of 16.9 kg/m2.

But 63% of participants remained at a BMI of 35 kg/m2 or higher and 13% failed to lose at least 10% of their bodyweight.

In line with the weight reductions, patients in both studies saw significant improvements in cardiovascular risk factors including dysglycemia, dyslipidemia, and high blood pressure. In the US study, the higher the residual excess BMI was, the more likely patients were to still have these risk factors.

The benefits of surgery were counterbalanced by some adverse events. A quarter of patients in the Swedish study required more surgical procedures (excluding plastic surgery) during follow-up. Of the 21 procedures, 11 were for small bowel obstruction and nine were for gallstones. In the US study, there were 13 upper endoscopies and 12 cholecystectomies among other procedures that were thought to be related to the initial surgery.

Around a third of patients in both studies had anemia, 30% and 78% of those in the Swedish and US studies, respectively, developed vitamin D deficiency, and 22% and 16% had low vitamin B12.